com.lmax.disruptor.WaitStrategy Maven / Gradle / Ivy
/*
* Copyright 2011 LMAX Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.lmax.disruptor;
/**
* Strategy employed for making {@link EventProcessor}s wait on a cursor {@link Sequence}.
*/
public interface WaitStrategy
{
/**
* Wait for the given sequence to be available. It is possible for this method to return a value
* less than the sequence number supplied depending on the implementation of the WaitStrategy. A common
* use for this is to signal a timeout. Any EventProcessor that is using a WaitStrategy to get notifications
* about message becoming available should remember to handle this case. The {@link BatchEventProcessor} explicitly
* handles this case and will signal a timeout if required.
*
* @param sequence to be waited on.
* @param cursor the main sequence from ringbuffer. Wait/notify strategies will
* need this as it's the only sequence that is also notified upon update.
* @param dependentSequence on which to wait.
* @param barrier the processor is waiting on.
* @return the sequence that is available which may be greater than the requested sequence.
* @throws AlertException if the status of the Disruptor has changed.
* @throws InterruptedException if the thread is interrupted.
* @throws TimeoutException if a timeout occurs before waiting completes (not used by some strategies)
*/
long waitFor(long sequence, Sequence cursor, Sequence dependentSequence, SequenceBarrier barrier)
throws AlertException, InterruptedException, TimeoutException;
/**
* Implementations should signal the waiting {@link EventProcessor}s that the cursor has advanced.
*/
void signalAllWhenBlocking();
}